Additive composition for spark-ignition engine fuels

ABSTRACT

where R represents an alkyl group having from 9 to 12 carbon atoms, inclusive, and n averages from about 4 to 7, inclusive, combined with a member selected from the group consisting of the imidazoline compounds of the formula   A synergistic, corrosion-preventive additive for use with sparkignition petroleum products such as gasoline which comprises an admixture of an alkylphenol ethoxylate compound of the formula wherein R2 is an alkyl or alkenyl of from 17 to 21 carbon atoms, inclusive. By virtue of the synergistic action developed by the two components of the composition, metallic surfaces in contact therewith are rendered resistent to corrosion caused by exposure to air, water, and gasoline, and overall engine maintenance is facilitated by virtue of the cleaning action attributable to the combination and particularly the inclusion of the alkylphenol ethoxylate component thereof.   wherein R1 represents an alkyl or alkenyl group having from 13 to 17 carbon atoms, inclusive, and imidazoline compounds of the formula

United States Patent 1191 Romans Dec. 23, 1975 1 ADDITIVE COMPOSITION FOR SPARK-IGNITION ENGINE FUELS [75] Inventor: Duane R. Romans, Kansas City, Mo.

[73] Assignee: Farmland Industries, Inc, Kansas City, Mo.

[22] Filed: Dec. 26, 1973 [211 App]. No.: 428,138

Primary Examiner-Daniel E. Wyman Assistant Examiner-Y. Harris-Smith Attorney, Agent, or Firm-Schmidt, Johnson, Hovey & Williams [57] ABSTRACT A synergistic, corrosion-preventive additive for use with spark-ignition petroleum products such as gasoline which comprises an admixture of an alkylphenol ethoxylate compound of the formula where R represents an alkyl group having from 9 to 12 carbon atoms, inclusive, and n averages from about 4 to 7, inclusive, combined with a member selected from the group consisting of the imidazoline compounds of the formula wherein R represents an alkyl or alkenyl group having from 13 to 17 carbon atoms, inclusive, and imidazoline compounds of the formula wherein R is an alkyl or alkenyl of from 17 to 21 carbon atoms, inclusive. By virtue of the synergistic action developed by the two components of the composition, metallic surfaces in contact therewith are rendered resistent to corrosion caused by exposure to air, water, and gasoline, and overall engine maintenance is facilitated by virtue of the cleaning action attributable to the combination and particularly the inclusion of the alkylphenol ethoxylate component thereof.

3 Claims, No Drawings ADDITIVE COMPOSITION FOR SPARK-IGNITION ENGINE FUELS BACKGROUND This invention relates to a corrosion-preventive additive composition for use with spark-ignition petroleum products such as gasoline or the like and which is capable of protecting the metallic surfaces of such engines from corrosion caused by exposure to air, water, and fuel and moreover aids in keeping such surfaces free of unwanted deposits thereon, thus facilitating overall engine maintenance. More specifically, the invention is concerned with a synergistic, two-component additive composition comprising a selected alkylphenol ethoxylate in conjunction with a member of a specific class of imidazoline compounds which when added to gasoline give enhanced protection against nonnally encountered types of engine corrosion.

Corrosion and deposit of undesirable contaminants such as gums or the like on the internal metallic surfaces of gasoline engines has been a persistent, costly and troublesome problem for the operators of such machines. Such corrosion and dirtying of engine components can be caused by exposure to air or moisture or even the gasoline fuel itself. In practice, it has been found that fuel filters and lines can become corroded or clogged by the presence of water and gum-forming materials in such fuels, which of course necessitates frequent cleaning. These maintenance problems are aggravated by the fact that moisture and other undesirable contaminants are almost invariably found to some degree in all gasoline, which in many instances results in breakdowns and constant costly repairs. It will be readily apparent that all of these problems detract from the optimum efficiency desirable in the operation of a gasoline engine, because the latter depends on an unimpeded, regular supply of fuel through the carburetion and fuel delivery system thereof, and on the general cleanliness of the internal engine components.

In response to the problems outlined above, a large number of additives have been proposed in the past for introduction into spark-ignition fuels. While a number of such additives have received wide-spread acceptance in the art, several persistent problems have arisen through the use thereof. Most importantly, while these prior additive compositions are capable of preventing corrosion of metallic surfaces continually exposed to, for example, gasoline, they are generally deficient in providing similar levels of protection to those engine components intermittently exposed to air or water. Thus, while the prior compositions find limited utility in preventing certain specific types of corrosion in gasoline engines, the latter are nevertheless susceptible to corrosion which is not efiectively arrested by the particular additive composition employed. As a result, overall engine maintenance is sacrificed because of the limited protection afforded by these prior additives.

Therefore, there is a need in the art for an effective additive composition for gasolines and like fuels which facilitates overall engine maintenance and is capable of giving enhanced, broad protection to the metallic surfaces of the internal engine components which are subjected to varying corrosive attacks from a number of different sources.

SUMMARY Accordingly, it has been discovered that an additive composition for spark-ignition engine fuels can be provided which gives enhanced protection against corrosion from air, water and the fuel itself, and moreover serves to prevent other undesirable deposits from forming on the internal components of the engine. Broadly, the composition comprises a synergistic, two-component system employing a selected class of alkylphenol ethoxylate compounds in conjunction with a select group of imidazoline compounds.

More specifically, the compositions of the present invention comprise an admixture employing an alkylphenol ethoxylate of the formula wherein R represents an alkyl group having from 9 to 12 carbon atoms, inclusive, and n, which represents the average number of ethylene oxide molecules reacted with the alkylphenol, is from about 4 to 7, inclusive.

The second component of the composition is a member selected from the group consisting of irnidazolines of the formula wherein R represents an alkyl or alkenyl group having from 13 to 17 carbon atoms, inclusive, and imidazolines of the formula where R represents an alkyl or alkenyl group of from 17 to 21 carbon atoms, inclusive.

It has been found that the components defined above act in a synergistic fashion to inhibit corrosion of metallic surfaces and to prevent deposition of undesirable contaminants on engine surfaces. More specifically, while single members of either of the above classes of compounds may in some instances give very little corrosion inhibition, combination of compounds within the scope of this invention give enhanced results that cannot be attributed to cumulative effect of the separate components. While the synergistic action of these compounds is not completely understood, it is believed that the latter in some fashion cooperate to deposit a relatively corrosion-impervious molecular layer upon metallic surfaces coming into contact therewith, to thereby achieve the enhanced corrosion prevention effects alluded to previously.

In particular embodiments of the invention, it has been determined that the alkylphenol ethoxylate component should be present in spark-ignition gasolines (generally defined as a hydrocarbon base fuel boiling in the range of from about 80 to 400F, and consisting primarily of hydrocarbons having from 4 to 12 carbon atoms) in an amount of from about 20 to 200 ppm. Likewise, the imidazoline is advantageously employed therein in amounts ranging from about to 100 ppm.

In the most preferred form of the invention, dodecylphenol reacted with an average of 7 ethylene oxide molecules is utilized at a level of about 80 ppm, and l-(2-aminoethyl)-2-tridecyl-2-imidazoline is employed in amounts totaling about 40 ppm. Consequently, the total additive concentration in the gasoline is approximately 120 ppm, and this level has proven to give excellent overall corrosion inhibition on engine surfaces.

DETAILED DESCRIPTION Representative compounds found to possess effective and synergistic activity in combined form as additive compositions with gasoline include the following:

Alkylphenol Ethoxylates:

nonylphenol reacted with an average of 4 ethylene oxide groups nonylphenol reacted with an average of 6 ethylene oxide groups (N-6) dodecylphenol reacted with an average of 5 ethylene oxide groups (DD-5) dodecylphenol reacted with an average of 7 ethylene oxide groups (DD-7) Imidazolines:

l-( Z-hydroxyethyl)-2-heptadecenyl l(2-hydroxyethyl )-2-uncosyl 2-imidazoline (2 1-H l-(2-aminoethyl)-2tridecyl -2-imidazoline l3-A) l-( 2-aminoethyl )-2-heptadecenyl -2-imidazoline l7-A) (The designation given in parenthesis for each compound is used hereinafter as needed to refer to the particular compounds.)

The alkylphenol ethoxylates were obtained commercially from the Thompson Hayward Chemical Company, Kansas City, Kan. One imidazoline, l-(2-hydroxylethyl)-2-heptadecenyl-2-imidazoline (l7-H) was purchased from the Diamond Shamrock Chemical Company under the tradename NOPCOGEN 22-0. The remaining imidazolines were synthesized according to the following conventional procedures.

The imidazolines designated l3-H and 2l-H were prepared by adding 0.1 moles of the proper carboxylic acid to 0.2 moles of 2-( 2-aminoethylamino)ethanol in a reaction flask. 4-5 times as much xylene (about ml.) as the water expected from the reaction (about 3.6 ml.) was also added to each flask, followed by heating to a temperature of about 250 C for a period of 46 hours until the theoretical amount of water had been liberated from the mixtures. The remaining xylene and 2-(2- aminoethylamino)ethanol was then removed by vacuum distillation at less than 1 mm. Hg. The crude prodnet was then recrystallized using a suitable organic solvent such as acetone.

Following recrystallization, the infrared spectrum of each compound showed only the imidazoline peak at about 1590-4610 cm with little or no amide peak at 1650 cm. Elemental analysis of compound 2l-H gave the following results:

C N C C H N O calculated 76.47 12.75 6.86 found 76.02 12.79 6.85

EXAMPLE I In order to confirm the rust prevention capabilities of the compositions of this invention as compared with the individual components thereof, the following test was devised. A series of spindles was made from No. 1018 cold rolled steel rod which was cut into 3 inch lengths and deburred. The spindles were then polished on a turning lathe operating at 2800 rpm by using coarse, medium and then fine emery cloth. The spindles were subsequently polished until no noticeable pits could be seen thereon, and they were then stored in hexane to prevent any surface corrosion.

In order to prepare gasoline samples containing the various additives, stock solutions of the respective imidazolines (0.664 mg/ml.) and alkylphenol ethoxylates (1.332 mg/ml.) were first made. For the imidazoline only test solutions, 3.00 ml. of the imidazoline stock solution was diluted to yield a total of 50 grams of gasoline containing approximately 40 ppm imidazoline.

Similarly, for the alkylphenol ethoxylate only solutions, 3.00 ml. of the ethoxylate stock solution was diluted to a total of 50 grams to give a gasoline sample having approximately ppm alkylphenol ethoxylate therein. The combination test solutions containing both the alkylphenol ethoxylate and imidazoline components at a level of 80 and 40 ppm respectively were prepared by admixing 3 ml. of each of the imidazoline and ethoxylate stock solutions and diluting to a total of 50 grams with gasoline. A control was also tested which contained untreated gasoline.

In order to determine the rust prevention capabilities of the various solutions prepared, 50 milliliter samples of gasoline with the defined additives therein were placed in 4 ounce bottles provided with a cap and polyethylene liner. A steel spindle was placed in each bottle, and the bottles were securely capped and placed on their sides for about 5 to 10 minutes in order to soak the spindle in the fuel. 25 milliliters of water was then added to each bottle, and the latter was capped and agitated in order to insure a uniform mixing of all of the phases within the bottle (i.e., air, fuel and water). Durthe caps were synergistic corrosion-inhibition on the steel spindles. A aling discomparison of the'results .obtained by the employment g, of the phases. of the additive compositions herein with the individual ndle was visually components thereof shows that in every case the comtervalsand recorded. For this position gave-markedly better protection against corrosion. Although the chemical interaction of the two KEY components of the .composition is not completely understood, it is apparentthata synergistic result obtains gz g z spot I through their use in gasoline as asingle additive com- Trace, wo mall spots. P 1 f T Small 816B first" For example, in the additive composition referred to ro 1 5 721 2 5% I in the Table as DD-7 +13-A which is l -(2-am inoe- M Medium rust, 10%-2s% thyl)-2-tridecyl-2-imidazoline plus" dodecylphenol regfi gg acted with an average of 7 ethylene oxide molecules, a

w 0 l5 significant degree of synergism results. Referring specifically to the rating at 30 days, it will be seen that the two component composition has completely prevented corrosion in both the air and fuel phases; this is to be contrasted with the single component data for both DD-7 and 13-A. In neither instance do these compounds alone give such enhanced corrosion inhibition when used as a gasoline addtive. In a similar fashion, it will be observed that all of the combined additive compositions tested above gave synergistic results to a greater or lesser degree. Likewise, all of the compounds within the classes defined for the imidazolines and alkylphenol ethoxylates were shown to be operable in a similar manner.

Having thus described the invention, what is claimed TABLE A= Air Phase F= Fuel Phase W= Water Phase The rust test data obtained in accordance with the methods defined above is given in the Table below. As

ing the testing period which followed,

periodically removed and'then returned to se position in conjunction with remixin The degree of rusting on each spi observed at various in purpose, the following key was employed.

can be seen, readings were taken at intervals of l, 16 and days in order to estimate the degree of rust coverage on each of the spindles. It will be noted that in certain instances single runs were made on different days with various test solutions, using identical methods and procedures. The majority of cases however, only a single test was performed. (In three instances completely separate runs were made including controls; the latter was necessitated because difi'erent samples of gasoline require separate control tests to insure meaningful corrosion inhibition data.)

Test Additive man Hn Mn M LLL LT TO T LLL LL TL 0 as new and desired to be secured by Letters Patent is:

1. In combination: a quantity of spark ignition fuel; an additive admixed with said fuel and taken from the group consisting of: A. from about 20 to 200 ppm, based upon the fuel,

of dodecylphenol ethoxylate containing an average of about 5 radicals of the formula -OCI-I- mnnnn nnn an Mn Hun HMM D-S. DD-7 and l7-H only readings:

nnn nn Mn M LLL LL 00 L LLL LL LL L at that time. control, N-6 and Zl-H only tests (80 WHHHH HHH an MH HH HMM positions, namely the midazoline, produce a n n nn Mn n Lor TT To r LLL LL LL L In the combination tests, a concentration of 80 ppm alkylphenol ethoxylate and 40 ppm imidazoline was employed.

It will be seen from a study of the foregoing Table that in every case the additive compositions in accor- A concentration of about 80 ppm was used in the alkylphenol ethoxylate only tests.

A concentration of about 40 ppm was used in the imidazoline only tests.

"'l'his data represents duplicate, identical runs made on different days in some instances. In this test, a single reading was taken after a three day period "In this test, the reading was taken at 15 days with the following control D Control, LLH; DD-S only LLM: DD-7 only LLH; and l7-H only LLMr dance with the invention gave enhanced corrosion resistance to the steel spindles at one or more time periods and in at least one of the three corrosion phases. Moreover, it is significant to note that the two a mi 0 e o e n. v .m mm M m Mm mnHHn nnn Mn Mn nun HMM v h LTOTL LLL LL MLT 0L0 000 u. em. LLLLLOLLL LT LL TTL OLO M. m o a .w m m M m e p Ill HHAAHHAA m s n nnaannA riirnlir H M m a 3353 a may m n +++++++s5ss 77 w w fl. 0 snnvt iiisfisgwssn d k cmnoonzl t NNNNNNNDDDD. ooo w u md 8 O--CH -CH and from about 10 to 100 ppm, based upon the fuel, of l-( 2-aminoethyl)-2- tridecyl-2-imidazoline.

2. The combination of claim 1 wherein said additive is about ppm, based upon the fuel, of dodecylphenol ethoxylate containing an average of about 7 radicals of the formula OCH CH and about 40 ppm, based upon the fuel of l-(2-aminoethyl)-2-tridecyl-2- imidazoline.

3. The combination of claim 1 wherein said fuel is gasoline. 

1. IN COMBINATION: A QUANTITY OF SPARK IGNITION FUEL; AN ADDITIVE ADMIXED WITH SAID FUEL AND TAKEN FROM THE GROUP CONSISTING OF: A. FROM ABOUT 20 TO 200 PPM, BASED UPON THE FUEL, OF DODECYLPHENOL ETHOXYLATE CONTAINING AN AVERAGE OF ABOUT 5 RADICALS OF THE FORMULA -O-CH2-CH2-, AND FROM ABOUT 10 TO 100 PPM, BASED UPON THE FUEL, OF 1-(2-HYDROXYETHYL)-2-UNCOSYL-2-IMIDAZOLINE; B. FROM ABOUT 20 TO 200 PPM. BASED UPON THE FUEL, OF DODECYLPHENOL ETHOXYLATE CONTAINING AN AVERAGE OF ABOUT 7 RADICALS OF THE FORMULA -O-CH2-CH2-, AND FROM ABOUT 10 TO 100 PPM, BASED UPON THE FUEL, OF 1-(2-HYDROXYETHYL)-2-UNCOSYL-2-IMIDAZOLINE; AND C. FROM ABOUT 20 TO 200 PPM, BASED UPON THE FUEL, OF DODECYLPHENOL ETHYOXYLATE CONTAINING AN AVERAGE OF ABOUT 7 RADICALS OF THE FORMULA -O-CH2-CH2-, AND FROM ABOUT 10 TO 100 PPM, BASED UPON THE FUEL, OF 1-(2-AMINOETHYL)-2-TRIDECYL-2-IMIDAZOLINE.
 2. The combination of claim 1 wherein said additive is about 80 ppm, based upon the fuel, of dodecylphenol ethoxylate containing an average of about 7 radicals of the formula -O-CH2-CH2-, and about 40 ppm, based upon the fuel of 1-(2-aminoethyl)-2-tridecyl-2-imidazoline.
 3. The combination of claim 1 wherein said fuel is gasoline. 